//
// Created by mac on 1/26/22.
//

#include <string>
using namespace std;
int getValue(char ch) {
    switch(ch) {
        case 'I': return 1;
        case 'V': return 5;
        case 'X': return 10;
        case 'L': return 50;
        case 'C': return 100;
        case 'D': return 500;
        case 'M': return 1000;
        default: return 0;
    }
}
int romanToInt(string s) {
    int sum = 0;
    int preNum = getValue(s[0]);
    for (int i = 1; i < s.length(); i++) {
        int num = getValue(s[i]);
        if (preNum < num) {
            sum -= preNum;
        } else {
            sum += preNum;
        }
        preNum = num;
    }
    sum += preNum;
    return sum;
}

